Magnetostratigraphy of the Toarcian Ammonitico Rosso limestone at Iznalloz, Spain

Abstract

The Iznalloz section (Betic cordillera, Spain) provides a continuous outcrop (20 m thick) of Toarcian ammonitico rosso limestones with all the ammonite zones defined in the Betic realm. The characteristic magnetization direction for each sample was obtained by detailed thermal demagnetization and was stable from about 450 to 560°C. The magnetic polarity sequence extends from the Polymorphum to the Aalensis ammonite zone, and covers the whole Toarcian stage. Thus this section presents a good pattern of the reversal succession during Toarcian times. Considering hiatuses of sampling and excluding single‐sample magnetozones, there does not seem to be any important change in the reversal rate during this period.